Optical path folding element, imaging lens module and electronic device

ABSTRACT

An optical path folding element includes an incident surface, a path folding surface and an exiting surface. The incident surface allows a light ray to pass into the optical path folding element. The path folding surface folds the light ray from the incident surface. The exiting surface allows the light ray to pass through and depart from the optical path folding element. At least one of the incident surface and the exiting surface includes an optical effective portion and at least one engaging structure symmetrically disposed around the optical effective portion. The engaging structure includes an annular surface portion and an inclined surface portion. The annular surface portion surrounds the optical effective portion, and the inclined surface portion is located between the annular surface portion and the optical effective portion. An angle between the annular surface portion and the inclined surface portion satisfies a specific condition.

RELATED APPLICATIONS

The present application is a continuation of the application Ser. No.16/159,828, filed on Oct. 15, 2018, which is a continuation of theapplication Ser. No. 15/292,215, filed on Oct. 13, 2016, U.S. Pat. No.10,133,037 issued on Nov. 20, 2018, and claims priority to Taiwanapplication serial number 105213079, filed on Aug. 26, 2016, the entirecontents of which are hereby incorporated herein by reference.

BACKGROUND Technical Field

The present disclosure relates to an optical path folding element andimaging lens module. More particularly, the present disclosure relatesto an optical path folding element and imaging lens module for anelectronic device.

Description of Related Art

Due to the popularity of personal electronic products and mobilecommunication products having camera functionalities, such as smartphones and tablet personal computers, the demand for compact imaginglens modules has been increasing. However, conventional telephoto lensassembly is limited by surface shapes or materials of lens elements sothat the volume cannot be reduced easily and price is too high, andfurther the application range is limited. Hence, one of the goals in theoptical lens industry is to find out how to satisfy market specificationand demand under the arrangement of telephoto characteristic,miniaturization and high image quality at the same time, and applicableto portable device, compact electronic device, zoom device, multiplelens assembly device and so on.

One of current solutions is favorable to utilize an optical path foldingelement, such as a prism, to fold and tilt an incident light ray forreducing the volume of the mechanism and an attenuation amount of thelight ray efficiently. However, how to stabilize the engagement betweenthe optical path folding element and other elements of the imaging lensmodule while minimizing the volume and keep a good alignment effect forproviding high image quality is very important to date.

SUMMARY

According to one aspect of the present disclosure, an optical pathfolding element includes an incident surface, a path folding surface andan exiting surface. The incident surface allows a light ray to pass intothe optical path folding element. The path folding surface folds thelight ray from the incident surface. The exiting surface allows thelight ray to pass through and depart from the optical path foldingelement. At least one of the incident surface and the exiting surfaceincludes an optical effective portion and at least one engagingstructure symmetrically disposed around the optical effective portion.The engaging structure includes an annular surface portion and aninclined surface portion. The annular surface portion surrounds theoptical effective portion, and the inclined surface portion is locatedbetween the annular surface portion and the optical effective portion.An angle between the annular surface portion and the inclined surfaceportion is θ1, and the following condition is satisfied: 95degrees<θ1<130 degrees.

According to another aspect of the present disclosure, an imaging lensmodule includes the abovementioned optical path folding element.

According to yet another aspect of the present disclosure, an electronicdevice includes the abovementioned imaging lens module.

According to further another aspect of the present disclosure, anoptical path folding element includes an incident surface, a pathfolding surface and an exiting surface. The incident surface allows alight ray to pass into the optical path folding element. The pathfolding surface folds the light ray from the incident surface. Theexiting surface allows the light ray to pass through and depart from theoptical path folding element. At least one of the incident surface andthe exiting surface includes an optical effective portion and at leastone engaging structure symmetrically disposed around the opticaleffective portion. The engaging structure includes an annular surfaceportion and a conical surface. The annular surface portion surrounds theoptical effective portion, and the conical surface is located betweenthe annular surface portion and the optical effective portion. An anglebetween the annular surface portion and the conical surface is θ2, andthe following condition is satisfied: 95 degrees<θ2<130 degrees.

According to still another aspect of the present disclosure, an imaginglens module includes the abovementioned optical path folding element.

According to yet another aspect of the present disclosure, an electronicdevice includes the abovementioned imaging lens module.

According to another aspect of the present disclosure, an imaging lensmodule includes the plastic barrel according to the foregoing aspect andan optical lens assembly, which is disposed in the plastic barrel andincludes at least one lens element.

According to another aspect of the present disclosure, an electronicdevice includes the imaging lens module according to the foregoingaspect.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure can be more fully understood by reading thefollowing detailed description of the embodiment, with reference made tothe accompanying drawings as follows:

FIG. 1A is a three dimensional view of an optical path folding elementaccording to a 1st example of the present disclosure;

FIG. 1B is a cross-sectional view of the optical path element accordingto the 1st example of the present disclosure;

FIG. 2A is a three dimensional view of an optical path folding elementaccording to a 2nd example of the present disclosure;

FIG. 2B is a cross-sectional view of the optical path element accordingto the 2nd example of the present disclosure;

FIG. 3A is a three dimensional view of an optical path folding elementaccording to a 3rd example of the present disclosure;

FIG. 3B is a cross-sectional view of the optical path element accordingto the 3rd example of the present disclosure;

FIG. 4A is a three dimensional view of an optical path folding elementaccording to a 4th example of the present disclosure;

FIG. 4B is a cross-sectional view of the optical path element accordingto the 4th example of the present disclosure;

FIG. 5A is a three dimensional view of an optical path folding elementaccording to a 5th example of the present disclosure;

FIG. 5B is a cross-sectional view of the optical path element accordingto the 5th example of the present disclosure;

FIG. 6 is a cross-sectional view of an imaging lens module according toa 6th example of the present disclosure;

FIG. 7 is a cross-sectional view of an imaging lens module according toa 7th example of the present disclosure;

FIG. 8 is a cross-sectional view of an imaging lens module according toan 8th example of the present disclosure;

FIG. 9 is a cross-sectional view of an imaging lens module according toa 9th example of the present disclosure;

FIG. 10 is a schematic view of an electronic device according to a 10thexample of the present disclosure;

FIG. 11 is a schematic view of an electronic device according to an 11thexample of the present disclosure; and

FIG. 12 is a schematic view of an electronic device according to a 12thexample of the present disclosure.

DETAILED DESCRIPTION

The present disclosure provides an optical path folding element, and theoptical path folding element includes an incident surface, a pathfolding surface and an exiting surface. The incident surface allows alight ray to pass into the optical path folding element. The pathfolding surface folds the light ray from the incident surface. Theexiting surface allows the light ray to pass through and depart from theoptical path folding element.

At least one of the incident surface and the exiting surface includes anoptical effective portion and at least one engaging structure. Theengaging structure is symmetrically disposed around the opticaleffective portion.

According to one embodiment of the present disclosure, the engagingstructure can include an annular surface portion and an inclined surfaceportion. The annular surface portion surrounds the optical effectiveportion, and the inclined surface portion is located between the annularsurface portion and the optical effective portion. When an angle betweenthe annular surface portion and the inclined surface portion is θ1, thefollowing condition is satisfied: 95 degrees<θ1<130 degrees. Thus, theengagement effect of the engaging structure and the alignment effect ofthe optical path folding element can be improved. Preferably, thefollowing condition is satisfied: 100 degrees<θ1<120 degrees.

According to another embodiment of the present disclosure, the engagingstructure can include an annular surface portion and a conical surface.Preferably, the conical surface is a closed ring for increasing theconvenience of the manufacturing process.

As mentioned above, the engaging structure is not limited to be disposedon the incident surface or the exiting surface. That is, the engagingstructure can be disposed on both of the two surfaces according to theneeds of the following application. Furthermore, there is a step betweenthe annular surface portion and the optical effective portion due to theconfiguration of the inclined surface portion. Thus, the optical pathfolding element can be engaged with other elements in the imaging lensmodule by the step for increasing the stability of the whole structure.

Moreover, the optical path folding element can be made of a plasticmaterial and is suitable to be applied in the imaging lens module whichis non wide-angle and has the demand of compact size.

In particular, the optical path folding element can be made of amateriel with a lower Abbe number, such as the EP series of Mitsubishigas chemical company, Inc (MGC) or the SP series of Teijin. Commonoptical plastic materials, such as the OKP series of Osaka gas chemical(OGC), also can be used in the present disclosure.

In the present disclosure, when the Abbe number of the optical pathfolding element is V, the following condition is satisfied: V<32.0.Thus, differences between deflection paths of light rays, which havedifferent wavelengths, in visible spectrum can be reduced. Preferably,the following condition is satisfied: V<25.0.

In addition, the path folding surface of the present disclosure caninclude a metallic layer covered thereon for folding the light ray fromthe incident surface. Preferably, the metallic layer is an aluminummetallic layer suitable for applying to an optical system with imagingdemands. The aluminum metallic layer is cheaper so that it is favorablefor reducing the cost in the following application. Furthermore, thelight ray is folded by 90 degrees when passing through the path foldingsurface for simplifying the optical structure. Moreover, a distancebetween a center of the incident surface and a center of the pathfolding surface can be equal to a distance between the center of thepath folding surface and a center of the exiting surface. Accordingly,the optical path folding element can further fit the requests of theoptical design, and thus, it will reduce the opportunities ofsacrificing the optical specifications under the specific condition.

In details, an area occupied by the optical effective portion is equalto or more than 40% of a total area of the incident surface or theexiting surface for expanding the light absorption range and maintainingthe requirements for high resolution and image quality of presentcompact imaging lens modules. In addition, the optical effective portioncan be a plane, spherical or aspheric area. Moreover, the appearance ofthe optical effective portion can be polygon-shaped, such as rectangularor octagonal.

When a width of the abovementioned inclined surface portion is L1, thefollowing condition is satisfied: 0.07 mm<L1<0.35 mm. Thus, thestability of the engagement between the optical path folding element andother elements of the imaging lens module can be enhanced while compactsize of the optical path folding element is maintained. In anotherembodiment of the present disclosure, when a width of the conicalsurface is L2, the following condition is satisfied: 0.07 mm<L2<0.35 mm.

The present disclosure further provides an imaging lens module includingthe optical path folding element according to any one of the twoembodiments as mentioned above. The optical path folding element can beengaged with at least one lens element or an opaque member of theimaging lens module through the engaging structure thereof. When theoptical path folding element is engaged with the lens element, theoptical path folding element can be aligned to an optical axis of thelens element for increasing the optical accuracy and maintaining highimage quality. When the optical path folding element is engaged with theopaque member, the stability of the whole imaging lens module can beincreased, and image quality of the imaging lens module will not beaffected due to the collision in the external environment. Inparticular, the opaque member can be but not limited to a cover, a baseor a barrel of the imaging lens module. Furthermore, the imaging lensmodule can be applied to 3D (three-dimensional) image capturingapplications, in products such as digital cameras, mobile devices,digital tablets, smart TVs, surveillance systems, motion sensing inputdevices, driving recording systems, rearview camera systems, andwearable devices.

Accordingly, an electronic device is further provided in the presentdisclosure for satisfying the requirements for high resolution and imagequality of present compact imaging lens modules. Preferably, theelectronic device can further include but not limited to a display, acontrol unit, a storage unit, a random access memory unit (RAM) or aread-only memory unit (ROM) or a combination thereof.

According to the aforementioned embodiments, a plurality of examples areprovided in cooperated with figures for details.

1st Embodiment

Please refer to FIG. 1A and FIG. 1B. FIG. 1A is a three dimensional viewof an optical path folding element 1000 according to a 1st example ofthe present disclosure, and FIG. 1B is a cross-sectional view of theoptical path element 1000 according to the 1st example of the presentdisclosure. As shown in FIG. 1A, the optical path folding element 1000of the 1st example includes an incident surface 1100, a path foldingsurface 1200 and an exiting surface 1300. The light ray I passes throughthe incident surface 1100 to enter the optical path folding element1000. After passing through the path folding surface 1200, the light rayI has a folding angle of 90 degrees and passes through the exitingsurface 1300 to depart from the optical path folding element 1000.

In particular, the optical path folding element 1000 is a triangularprism, and the optical path folding element 1000 is made of a plasticmaterial. Thereby, the optical path folding element 100 can be appliedin an imaging lens module which has the demand of compact size.

In the 1st example, the exiting surface 1300 of the optical path foldingelement 1000 includes an optical effective portion 1400 and an engagingstructure 1500. The engaging structure 1500 includes an annular surfaceportion 1501 and an inclined surface portion 1502. As shown in FIG. 1A,the optical effective portion 1400 is a rectangular-shaped portion. Theannular surface portion 1501 is symmetrically disposed around theoptical effective portion 1400, that is, the annular surface portion1501 surrounds the optical effective portion 1400 continuously. Theinclined surface portion 1502 is located between the annular surfaceportion 1501 and the optical effective portion 1400. More particularly,the inclined surface portion 1502 includes four trapezoidal surfacescorresponding to the optical effective portion 1400 which is therectangular-shaped portion. Each of the four trapezoidal surfaces islocated between each side of the optical effective portion 1400 and theannular surface portion 1501, respectively.

As shown in FIG. 1B, the annular surface portion 1501 and the exitingsurface 1300 are coplanar. The optical effective portion 1400 and theinclined surface portion 1502 protrude from the exiting surface 1300,that is, there is a step between the optical effective portion 1400 andthe annular surface portion 1501 due to the configuration of theinclined surface portion 1502. Accordingly, as shown in thecross-sectional view of the optical path folding element 1000, theexiting surface 1300, the optical effective portion 1400 and theinclined surface portion 1502 form a trapezoid protrusion. A top surfaceof the trapezoid protrusion is the optical effect portion 1400, and asidewall of the trapezoid protrusion is one of the trapezoidal surfacesof the inclined surface portion 1502. Preferably, an angle between theannular surface portion 1501 and the inclined surface portion 1502 isθ1, and a width of the inclined surface portion 1502 is L1. When theangle θ1 and the width L1 of the inclined surface portion 1502 satisfy aspecific condition, the engagement effect of the engaging structure 1500and the alignment effect of the optical path folding element 1000 can beimproved for maintaining high structural stability and image qualityunder the request of miniaturization.

Please refer to Table 1 as follows, the conditions, such as the materialand the Abbe number of the optical path folding element 1000, a ratiobetween an area occupied by the optical effective portion 1400 and atotal area of the exiting surface 1300, the angle θ1 between the annularsurface portion 1501 and the inclined surface portion 1502 and the widthL1 of the inclined surface portion 1502, are listed therein.

TABLE 1 (1st Example) Abbe number 20.4 Material PlasticManufactor/Product series MGC/EP Ratio between an area occupied byoptical 50 effective portion and a total area of exiting surface (%) θ1110 (degrees) L1 0.21 (mm)

The engaging structure 1500 can be manufactured through an injectionmolding process by a mold, which has an appearance corresponding to theabovementioned features of the engaging structure 1500, at the same timewith the optical path folding element 1000. The engaging structure 1500of the optical path folding element 1000 also can be manufactured bypasting a trapezoid protrusion on the exiting surface 1300, andpreferably the materials of the trapezoid protrusion can be the samewith the materials of the optical path folding element 1000. However,the manufacturing process of the optical path folding element 1000 isnot the main feature of the present disclosure and will not be furtherdescribed herein.

2nd Example

Please refer to FIG. 2A and FIG. 2B. FIG. 2A is a three dimensional viewof an optical path folding element 2000 according to a 2nd example ofthe present disclosure, and FIG. 2B is a cross-sectional view of theoptical path element 2000 according to the 2nd example of the presentdisclosure. As shown in FIG. 2A, the optical path folding element 2000of the 2nd example is a triangular prism and includes an incidentsurface 2100, a path folding surface 2200 and an exiting surface 2300.The light ray I passes through the incident surface 2100 to enter theoptical path folding element 2000. After passing through the pathfolding surface 2200, the light ray I has a folding angle of 90 degreesand passes through the exiting surface 2300 to depart from the opticalpath folding element 2000.

In the 2nd example, the exiting surface 2300 of the optical path foldingelement 2000 includes an optical effective portion 2400 and an engagingstructure 2500. In particular, the optical effective portion 2400 is arectangular-shaped portion. The engaging structure 2500 includes anannular surface portion 2501 and an inclined surface portion 2502. Theannular surface portion 2501 is symmetrically disposed around theoptical effective portion 2400, that is, the annular surface portion2501 surrounds the optical effective portion 2400 continuously. Theinclined surface portion 2502 is located between the annular surfaceportion 2501 and the optical effective portion 2400. More particularly,the inclined surface portion 2502 includes four trapezoidal surfacescorresponding to the optical effective portion 2400 which is therectangular-shaped portion. Each of the four trapezoidal surfaces islocated between each side of the optical effective portion 2400 and theannular surface portion 2501, respectively.

As shown in FIG. 2B, the annular surface portion 2501 and the exitingsurface 2300 are coplanar. The optical effective portion 2400 and theinclined surface portion 2502 protrude from the exiting surface 2300,and therefore, there is a step between the optical effective portion2400 and the annular surface portion 2501 due to the configuration ofthe inclined surface portion 2502. Accordingly, as shown in thecross-sectional view of the optical path folding element 2000, theexiting surface 2300, the optical effective portion 2400 and theinclined surface portion 2502 form a trapezoid protrusion. A top surfaceof the trapezoid protrusion is the optical effect portion 2400, and asidewall of the trapezoid protrusion is one of the trapezoidal surfacesof the inclined surface portion 2502. Preferably, an angle between theannular surface portion 2501 and the inclined surface portion 2502 isθ1, and a width of the inclined surface portion 2502 is L1. When theangle θ1 and the width L1 of the inclined surface portion 2502 satisfy aspecific condition, the engagement effect of the engaging structure 2500and the alignment effect of the optical path folding element 2000 can beimproved for maintaining high structural stability and image qualityunder the request of miniaturization.

Please refer to Table 2, the conditions, such as the material and theAbbe number of the optical path folding element 2000, a ratio between anarea occupied by the optical effective portion 2400 and a total area ofthe exiting surface 2300, the angle θ1 between the annular surfaceportion 2501 and the inclined surface portion 2502 and the width L1 ofthe inclined surface portion 2502, are listed therein.

TABLE 2 (2nd Example) Abbe number 19.5 Material PlasticManufactor/Product series MGC/EP Ratio between an area occupied byoptical 82 effective portion and a total area of exiting surface (%) θ1105 (degrees) L1 0.21 (mm)

As shown in Table 2, it is different from the 1st example that a ratiobetween an area occupied by the optical effective portion 2400 and atotal area of the exiting surface 2300 is 82% to increase the lightabsorption range efficiently for satisfying the requirements for highresolution and image quality of present compact optical elements.

3rd Example

Please refer to FIG. 3A and FIG. 3B. FIG. 3A is a three dimensional viewof an optical path folding element 3000 according to a 3rd example ofthe present disclosure, and FIG. 3B is a cross-sectional view of theoptical path element 3000 according to the 3rd example of the presentdisclosure. As shown in FIG. 3A, the optical path folding element 3000of the 3rd example is a triangular prism and includes an incidentsurface 3100, a path folding surface 3200 and an exiting surface 3300.The light ray I passes through the incident surface 3100 to enter theoptical path folding element 3000. After passing through the pathfolding surface 3200, the light ray I has a folding angle of 90 degreesand passes through the exiting surface 3300 to depart from the opticalpath folding element 3000.

In the 3rd example, the exiting surface 3300 of the optical path foldingelement 3000 includes an optical effective portion 3400 and an engagingstructure 3500. It is different from the 1st example that the opticaleffective portion 3400 is an octagonal-shaped portion. The engagingstructure 3500 includes an annular surface portion 3501 and an inclinedsurface portion 3502. The annular surface portion 3501 is symmetricallydisposed around the optical effective portion 3400, that is, the annularsurface portion 3501 surrounds the optical effective portion 3400continuously. The inclined surface portion 3502 is located between theannular surface portion 3501 and the optical effective portion 3400.More particularly, the inclined surface portion 3502 includes eighttrapezoidal surfaces corresponding to the optical effective portion 3400which is the octagonal-shaped portion. Each of the eight trapezoidalsurfaces is located between each side of the optical effective portion3400 and the annular surface portion 3501, respectively.

As shown in FIG. 3B, the annular surface portion 3501 and the exitingsurface 3300 are coplanar. The optical effective portion 3400 and theinclined surface portion 3502 protrude from the exiting surface 3300,and therefore, there is a step between the optical effective portion3400 and the annular surface portion 3501 due to the configuration ofthe inclined surface portion 3502. Preferably, an angle between theannular surface portion 3501 and the inclined surface portion 3502 isθ1, and a width of the inclined surface portion 3502 is L1. When theangle θ1 and the width L1 of the inclined surface portion 3502 satisfy aspecific condition, the engagement effect of the engaging structure 3500and the alignment effect of the optical path folding element 3000 can beimproved for maintaining high structural stability and image qualityunder the request of miniaturization.

Please refer to Table 3, the conditions, such as the material and theAbbe number of the optical path folding element 3000, a ratio between anarea occupied by the optical effective portion 3400 and a total area ofthe exiting surface 3300, the angle θ1 between the annular surfaceportion 3501 and the inclined surface portion 3502 and the width L1 ofthe inclined surface portion 3502, are listed therein.

TABLE 3 (3rd Example) Abbe number 23.4 Material PlasticManufactor/Product series OGC/OKP Ratio between an area occupied byoptical 79 effective portion and a total area of exiting surface (%) θ1115 (degrees) L1 0.22 (mm)

As shown in Table 3, it is different from the 1st example that a ratiobetween an area occupied by the optical effective portion 3400 and atotal area of the exiting surface 3300 is 79% to increase the lightabsorption range efficiently for satisfying the requirements for highresolution and image quality of present compact optical elements.Moreover, in the 3rd example, the angle θ1 between the annular surfaceportion 3501 and the inclined surface portion 3502 is larger than thatof the 1st example so that the stability of the whole imaging lensmodule using thereof will be enhanced.

4th Example

Please refer to FIG. 4A and FIG. 4B. FIG. 4A is a three dimensional viewof an optical path folding element 4000 according to a 4th example ofthe present disclosure, and FIG. 4B is a cross-sectional view of theoptical path element 4000 according to the 4th example of the presentdisclosure. As shown in FIG. 4A, the optical path folding element 4000of the 4th example is a triangular prism and includes an incidentsurface 4100, a path folding surface 4200 and an exiting surface 4300.The light ray I passes through the incident surface 4100 to enter theoptical path folding element 4000. After passing through the pathfolding surface 4200, the light ray I has a folding angle of 90 degreesand passes through the exiting surface 4300 to depart from the opticalpath folding element 4000.

In the 4th example, the exiting surface 4300 of the optical path foldingelement 4000 includes an optical effective portion 4400 and an engagingstructure 4500. The optical effective portion 4400 of the 4th example isa circular-shaped portion, and further, the engaging structure 4500includes an annular surface portion 4501 and a conical surface 4502. Theannular surface portion 4501 surrounds the optical effective portion4400, and the conical surface 4502 is located between the annularsurface portion 4501 and the optical effective portion 4400. Preferably,the conical surface 4502 is a closed ring for increasing the convenienceof the manufacturing process.

As shown in FIG. 4B, the annular surface portion 4501 and the exitingsurface 4300 are coplanar. The optical effective portion 4400 and theconical surface 4502 protrude from the exiting surface 4300, andtherefore, there is a step between the optical effective portion 4400and the annular surface portion 4501 due to the configuration of theconical surface 4502. Preferably, an angle between the annular surfaceportion 4501 and the conical surface 4502 is θ2, and a width of theconical surface 4502 is L2. When the angle θ2 and the width L2 of theconical surface 4502 satisfy a specific condition, the engagement effectof the engaging structure 4500 and the alignment effect of the opticalpath folding element 4000 can be improved for maintaining highstructural stability and image quality under the request ofminiaturization.

Please refer to Table 4, the conditions, such as the material and theAbbe number of the optical path folding element 4000, a ratio between anarea occupied by the optical effective portion 4400 and a total area ofthe exiting surface 4300, the angle θ2 between the annular surfaceportion 4501 and the conical surface 4502 and the width L2 of theconical surface 4502, are listed therein.

TABLE 4 (4th Example) Abbe number 23.3 Material PlasticManufactor/Product series Teijin/SP Ratio between an area occupied byoptical 45 effective portion and a total area of exiting surface (%) Θ2110 (degrees) L2 0.32 (mm)

5th Example

Please refer to FIG. 5A and FIG. 5B. FIG. 5A is a three dimensional viewof an optical path folding element 5000 according to a 5th example ofthe present disclosure, and FIG. 5B is a cross-sectional view of theoptical path element 5000 according to the 5th example of the presentdisclosure. As shown in FIG. 5A, the optical path folding element 5000of the 5th example is a triangular prism and includes an incidentsurface 5100, a path folding surface 5200 and an exiting surface 5300.The light ray I passes through the incident surface 5100 to enter theoptical path folding element 5000. After passing through the pathfolding surface 5200, the light ray I has a folding angle of 90 degreesand passes through the exiting surface 5300 to depart from the opticalpath folding element 5000.

In the 5th example, the exiting surface 5300 of the optical path foldingelement 5000 includes an optical effective portion 5400 and an engagingstructure 5500. In particular, the optical effective portion 5400 of the5th example is a circular-shaped portion. The engaging structure 5500includes an annular surface portion 5501 and a conical surface 5502.Moreover, the annular surface portion 5501 surrounds the opticaleffective portion 5400, and the conical surface 5502 is located betweenthe annular surface portion 5501 and the optical effective portion 5400.Preferably, the conical surface 5502 is a closed ring for increasing theconvenience of the manufacturing process.

As shown in FIG. 5B, the annular surface portion 5501 and the exitingsurface 5300 are also coplanar. However, the optical effective portion5400 and the conical surface 5502 are recessed into the exiting surface5300 for further minimizing an occupied space of the optical pathfolding element 5000 and satisfying the demand of compact size. Indetails, the optical path folding element 5000 has a circular recessformed on the exiting surface 5300. A bottom surface of the circularrecess is the optical effective portion 5400, and further, a sidewall ofthe circular recess is the conical surface 5502. Preferably, an anglebetween the annular surface portion 5501 and the conical surface 5502 isθ2, and a width of the conical surface 5502 is L2. When the angle θ2 andthe width L2 of the conical surface 5502 satisfy a specific condition,the engagement effect of the engaging structure 5500 and the alignmenteffect of the optical path folding element 5000 can be improved formaintaining the high structural stability and image quality under therequest of miniaturization.

Please refer to Table 5, the conditions, such as the material and theAbbe number of the optical path folding element 5000, a ratio between anarea occupied by the optical effective portion 5400 and a total area ofthe exiting surface 5300, the angle θ2 between the annular surfaceportion 5501 and the conical surface 5502 and the width L2 of theconical surface 5502, are listed therein.

TABLE 5 (5th Example) Abbe number 21.4 Material PlasticManufactor/Product series OGC/OKP Ratio between an area occupied byoptical 29 effective portion and a total area of exiting surface (%) Θ2110 (degrees) L2 0.32 (mm)

6th Example

Please refer to FIG. 6, which is a cross-sectional view of an imaginglens module 100 according to a 6th example of the present disclosure. Asshown in FIG. 6, the imaging lens module 100 includes an opaque member110, an optical lens assembly 120 and an optical path folding element6000. The optical lens assembly 120 and the optical path folding element6000 are located inside the opaque member 110.

In the 6th example, the opaque member 110 is a cover of the imaging lensmodule 100 for protecting the assembled elements from being affected bythe external environment. In particular, the opaque member 110 includesan object-end portion 111, a tube portion 112 and an image-end portion113. The object-end portion 111 includes an object-end opening 111 a,and the image-end portion 113 includes an image-end opening 113 a.

In details, the object-end portion 111 faces toward an imaged object(not shown herein) and is provided for disposing the optical pathfolding element 6000 therein. The tube portion 112 is provided fordisposing a plurality of lens elements therein, and the image-endportion 113 is closest to an image surface P in the imaging lens module100.

In the 6th example, the optical lens assembly 120 includes, in orderfrom the object-end portion 111 to the image-end portion 113 along anoptical axis, a first lens element 121, a second lens element 122, athird lens element 123 and a fourth lens element 124.

In addition, the lens element of the optical lens assembly 120 can bemade of plastic or glass materials. When the lens element is made of theplastic material, manufacturing costs can be effectively reduced. Whenthe lens elements are made of glass materials, the distribution of therefractive power of the optical photographing assembly may be moreflexible to design. Moreover, the optical lens assembly 120 can includeother optical elements (their reference numerals are omitted), such asspacers, light blocking sheets and so on.

According to FIG. 6, the structure of the optical path folding element6000 of the 6th example is approximately the same with the 1st example,the 2nd example and the 3rd example. That is, the optical path foldingelement 6000 is a triangular prism and includes an incident surface6100, a path folding surface 6200 and an exiting surface 6300.Accordingly, the light ray passes through the object-end opening 111 aand the incident surface 6100 to enter the optical path folding element6000, which is located in the object-end portion 111. After passingthrough the path folding surface 6200, the folded light ray departs fromthe optical path folding element 6000 through the exiting surface 6300and then enters into the optical lens assembly 120, which is located inthe tube portion 112. Finally, the light ray departs from the opticallens assembly 120 and passes through the image-end opening 113 a toimage on the image surface P.

The difference of the 6th example is that the incident surface 6100 ofthe optical path folding element 6000 includes an optical effectiveportion 6400 and an engaging structure 6500. In particular, the engagingstructure 6500 includes an annular surface portion 6501 and an inclinedsurface portion 6502. The inclined surface portion 6502 is locatedbetween the annular surface portion 6501 and the optical effectiveportion 6400. Thus, there is a step between the optical effectiveportion 6400 and the annular surface portion 6501 due to theconfiguration of the inclined surface portion 6502.

As shown in a partial enlarged view of FIG. 6, the optical path foldingelement 6000 is engaged with two sides of the object-end opening 111 aof the opaque member 110 through the step which is between the opticaleffective portion 6400 and the annular surface portion 6501. The twosides of the object-end opening 111 a can further include at least oneengaging member (not shown herein) for stabilizing the engagementbetween the optical path folding element 6000 and the opaque member 110.Furthermore, an angle θ1 between the annular surface portion 6501 andthe inclined surface portion 6502 is 105 degrees, and a width L1 of theinclined surface portion 6502 is 0.11 mm. Thus, the stability of thewhole structure can be enhanced by the engagement between the engagingstructure 6500 of the optical path folding element 6000 and the opaquemember 110.

7th Example

Please refer to FIG. 7, which is a cross-sectional view of an imaginglens module 200 according to a 7th example of the present disclosure. Asshown in FIG. 7, the imaging lens module 200 includes an opaque member210, an optical lens assembly 220 and an optical path folding element7000. The optical lens assembly 220 and the optical path folding element7000 are located inside the opaque member 210.

In the 7th example, the opaque member 210 is a cover of the imaging lensmodule 200 for protecting the assembled elements from being affected bythe external environment. In particular, the opaque member 210 includesan object-end portion 211, a tube portion 212 and an image-end portion213.

In details, the object-end portion 211 faces toward an imaged object(not shown herein) and is provided for disposing the optical pathfolding element 7000 therein. The tube portion 212 is provided fordisposing a plurality of lens elements therein, and the image-endportion 213 is closest to an image surface P in the imaging lens module200.

In the 7th example, the optical lens assembly 220 includes, in orderfrom the object-end portion 211 to the image-end portion 213 along anoptical axis, a first lens element 221, a second lens element 222, athird lens element 223 and a fourth lens element 224. The optical lensassembly 220 can include other optical elements (their referencenumerals are omitted), such as spacers, light blocking sheets and so on.

As shown in FIG. 7, the structure of the optical path folding element7000 of the 7th example is approximately the same with the 1st example,the 2nd example and the 3rd example. That is, the optical path foldingelement 7000 is a triangular prism and includes an incident surface7100, a path folding surface 7200 and an exiting surface 7300. Moreover,the exiting surface 7300 of the optical path folding element 7000includes an optical effective portion 7400 and an engaging structure7500. The engaging structure 7500 includes an annular surface portion7501 and an inclined surface portion 7502. In particular, the inclinedsurface portion 7502 is located between the annular surface portion 7501and the optical effective portion 7400. Thus, there is a step betweenthe optical effective portion 7400 and the annular surface portion 7501due to the configuration of the inclined surface portion 7502.

Accordingly, the light ray passes through the incident surface 7100 ofthe optical path folding element 7000, which is located in theobject-end portion 111, to enter therein and is folded by 90 degreesusing the path folding surface 7200. Then, the folded light ray departsfrom the optical path folding element 7000 through the exiting surface7300 and then enters into the optical lens assembly 220, which islocated in the tube portion 212. Finally, the light ray departs from theoptical lens assembly 220 and passes through the image-end portion 213to image on the image surface P.

The difference of the 7th example is that the central portion of theoptical effective portion 6400 is a concave spherical surface. Inaddition, as shown in a partial enlarged view of FIG. 7, there are aplurality of engaging members 212 a formed at a connection area betweenthe tube portion 212 and the object-end portion 211 of the opaque member210. Thus, the optical path folding element 7000 can be engaged with theengaging elements 212 a through the step which is between the opticaleffective portion 7400 and the annular surface portion 7501. Inparticular, the aforementioned engaging element 212 a can be but notlimited to a protrusion. More particularly, the engaging elements 212 aalso can be an engaging structure having a square opening. Furthermore,the engaging elements 212 a can be integrated with the opaque member210. Preferably, an angle θ1 between the annular surface portion 7501and the inclined surface portion 7502 is 115 degrees, and a width L1 ofthe inclined surface portion 7502 is 0.19 mm. Thus, the stability of thewhole structure can be improved.

8th Example

Please refer to FIG. 8, which is a cross-sectional view of an imaginglens module 300 according to an 8th example of the present disclosure.As shown in FIG. 8, the imaging lens module 300 includes a cover 310, anoptical lens assembly 320 and an optical path folding element 8000. Theoptical lens assembly 320 and the optical path folding element 8000 arelocated inside the cover 310. In particular, the cover 310 is providedfor protecting the assembled elements from being affected by theexternal environment.

In the 8th example, the optical lens assembly 320 includes four lenselements. In particular, the elements covered by the cover 310 of theimaging lens module 300 are, in order from an object side to an imageside along an optical axis, the optical path folding element 8000, afirst lens element 321, a second lens element 322, a third lens element323 and a fourth lens element 324 of the optical lens assembly 320. Theoptical lens assembly 320 can include other optical elements (theirreference numerals are omitted), such as spacers, light blocking sheetsand so on.

According to FIG. 8, the structure of the optical path folding element8000 of the 8th example is approximately the same with the 4th example.That is, the optical path folding element 8000 is a triangular prism andincludes an incident surface 8100, a path folding surface 8200 and anexiting surface 8300. Moreover, the exiting surface 8300 of the opticalpath folding element 8000 includes an optical effective portion 8400 andan engaging structure 8500. The engaging structure 8500 includes anannular surface portion 8501 and a conical surface 8502. In particular,the conical surface 8502 is located between the annular surface portion8501 and the optical effective portion 8400. Thus, there is a stepbetween the optical effective portion 8400 and the annular surfaceportion 8501 due to the configuration of the conical surface 8502.

Accordingly, the light ray passes through the incident surface 8100 toenter the optical path folding element 8000 and is folded by 90 degreesusing the path folding surface 8200. Then, the folded light ray departsfrom the optical path folding element 8000 through the exiting surface8300 and then enters into the optical lens assembly 320. Finally, thelight ray departs from the optical lens assembly 320 to image on theimage surface P.

In the 8th example, the optical path folding element 6000 is engagedwith the opaque member 110 of the imaging lens module 100. However, inthe 8th example, the optical path folding element 8000 is engaged withthe first lens element 321 of the optical lens assembly 320. In details,another engaging structure (not shown herein) can be further formed inan off-axial region of the first lens element 321 to be engaged with theengaging structure 8500 of the optical path folding element 8000 forfixing the optical path folding element 8000.

As shown in a partial enlarged view of FIG. 8, the first lens element321 is a concave lens element. In addition, the first lens element 321can be fixed in the cover 310 by the structural design of the cover 310.Thus, the optical path folding element 8000 leans against two sides ofthe concave surface of the first lens element 321 by the step, which isbetween the optical effective 8400 and the annular surface portion 8501,for fixing. In particular, an angle θ2 between the annular surfaceportion 8501 and the conical surface 8502 is 105 degrees, and a width L2of the conical surface 8502 is 0.11 mm. Thus, the stability of the wholestructure can be improved.

9th Example

Please refer to FIG. 9, which is a cross-sectional view of an imaginglens module 400 according to a 9th example of the present disclosure. Asshown in FIG. 9, the imaging lens module 400 can include a cover 410, anoptical lens assembly 420 and an optical path folding element 9000. Theoptical lens assembly 420 and the optical path folding element 9000 arelocated inside the cover 410. In particular, the cover 410 is providedfor protecting the assembled elements from being affected by theexternal environment.

In the 9th example, the optical lens assembly 420 includes four lenselements. In particular, the elements covered by the cover 410 of theimaging lens module 400 are, in order from an object side to an imageside along an optical axis, the optical path folding element 9000, afirst lens element 421, a second lens element 422, a third lens element423 and a fourth lens element 424 of the optical lens assembly 420. Theoptical lens assembly 420 can include other optical elements (theirreference numerals are omitted), such as spacers, light blocking sheetsand so on.

According to FIG. 9, the structure of the optical path folding element9000 of the 9th example is approximately the same with the 5th example.That is, the optical path folding element 9000 is a triangular prism andincludes an incident surface 9100, a path folding surface 9200 and anexiting surface 9300. Moreover, the exiting surface 9300 of the opticalpath folding element 9000 includes an optical effective portion 9400 andan engaging structure 9500. The engaging structure 9500 includes anannular surface portion 9501 and a conical surface 9502. It is notedthat, in the 9th example, the optical effective portion 9400 and theconical surface 9502 are recessed into the exiting surface 9300.

Accordingly, the light ray passes through the incident surface 9100 toenter the optical path folding element 9000 and is folded by 90 degreesusing the path folding surface 9200. Then, the folded light ray departsfrom the optical path folding element 9000 through the exiting surface9300 and then enters into the optical lens assembly 420. Finally, thelight ray departs from the optical lens assembly 420 to image on theimage surface P.

In the 9th example, the optical path folding element 9000 is engagedwith the first lens element 421 of the optical lens assembly 420 as sameas the 8th example. However, an annular notch 421 a is formed in theoff-axial region (that is, the two sides of the concave surface) of thelens element although the first lens element 421 is also a concave lenselement as same as the 8th example. As shown in a partial enlarged viewof FIG. 9, the optical path folding element 9000 is engaged with theannular notch 421 a of the first lens element 421 by the step, which isbetween the optical effective 9400 and the annular surface portion 9501,for fixing. In details, the step is able to be cooperated with theannular notch 421 a because the conical surface 9502 is the closed ring.In particular, an angle θ2 between the annular surface portion 9501 andthe conical surface 9502 is 115 degrees, and a width L2 of the conicalsurface 9502 is 0.19 mm. Thus, the stability of the whole structure canbe improved.

10th Example

Please refer to FIG. 10, which is a schematic view of an electronicdevice 10 according to a 10th example of the present disclosure. Theelectronic device 10 of the 10th embodiment is a smart phone andincludes an imaging lens module 500. The imaging lens module 500 can bethe abovementioned imaging lens module according to any of the 6thexample, the 7th example, the 8th example and the 9th example. Theimaging lens module 500 includes an optical path folding element (notshown herein) according to the present disclosure. Therefore, it isfavorable for enhancing the image quality so as to satisfy therequirements of high-end optical systems with camera functionalities.Furthermore, the electronic device 10 can further include an imagesensor (not shown herein), in which the image sensor is disposed on animage surface (not shown herein) of the imaging lens module 500.Preferably, the electronic device 10 can further include but not limitedto a display, a control unit, a storage unit, a random access memoryunit (RAM), a read-only memory unit (ROM) or a combination thereof.

11th Example

Please refer to FIG. 11, which is a schematic view of an electronicdevice 20 according to an 11th example of the present disclosure. Theelectronic device 20 of the 11th example is a tablet. The electronicdevice 20 includes an imaging lens module 600. The imaging lens module600 can be the abovementioned imaging lens module according to any ofthe 6th example, the 7th example, the 8th example and the 9th example.The imaging lens module 600 includes an optical path folding element(not shown herein) according to the present disclosure.

12th Example

Please refer to FIG. 12, which is a schematic view of an electronicdevice 30 according to a 12th example of the present disclosure. Theelectronic device 30 of the 12th example is a wearable device. Theelectronic device 30 includes an imaging lens module 700. The imaginglens module 700 can be the abovementioned imaging lens module accordingto any of the 6th example, the 7th example, the 8th example and the 9thexample. The imaging lens module 700 includes an optical path foldingelement (not shown herein) according to the present disclosure.

Although the present disclosure has been described in considerabledetail with reference to certain embodiments thereof, other embodimentsare possible. Therefore, the spirit and scope of the appended claimsshould not be limited to the description of the embodiments containedherein.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the structure of the presentdisclosure without departing from the scope or spirit of the disclosure.In view of the foregoing, it is intended that the present disclosurecover modifications and variations of this disclosure provided they fallwithin the scope of the following claims.

What is claimed is:
 1. An optical path folding element, comprising: anincident surface allowing a light ray to pass into the optical pathfolding element; a path folding surface folding the light ray from theincident surface; and an exiting surface allowing the light ray to passthrough and depart from the optical path folding element; wherein atleast one of the incident surface and the exiting surface comprises: anoptical effective portion; and at least one engaging structuresurroundingly disposed around the optical effective portion andcomprising: an annular surface portion surrounding the optical effectiveportion; and an inclined surface portion located between the annularsurface portion and the optical effective portion; wherein a width ofthe inclined surface portion is L1, and the following condition issatisfied:0.07 mm<L1<0.35 mm.
 2. The optical path folding element of claim 1,wherein the optical path folding element is made of a plastic material.3. The optical path folding element of claim 2, wherein the path foldingsurface comprises an aluminum metallic layer covered thereon.
 4. Theoptical path folding element of claim 2, wherein the light ray is foldedby 90 degrees when passing through the path folding surface.
 5. Theoptical path folding element of claim 2, wherein a distance between acenter of the incident surface and a center of the path folding surfaceis equal to a distance between the center of the path folding surfaceand a center of the exiting surface.
 6. The optical path folding elementof claim 2, wherein an area occupied by the optical effective portion isequal to or more than 40% of a total area of the incident surface or theexiting surface.
 7. An imaging lens module, comprising: the optical pathfolding element of claim
 1. 8. The imaging lens module of claim 7,wherein the imaging lens module comprises at least one lens element, andthe lens element is engaged with the engaging structure.
 9. The imaginglens module of claim 7, wherein the imaging lens module comprises atleast one opaque member, and the opaque member is engaged with theengaging structure.
 10. An electronic device, comprising: the imaginglens module of claim
 7. 11. An optical path folding element, comprising:an incident surface allowing a light ray to pass into the optical pathfolding element; a path folding surface folding the light ray from theincident surface; and an exiting surface allowing the light ray to passthrough and depart from the optical path folding element; wherein atleast one of the incident surface and the exiting surface comprises: anoptical effective portion; and at least one engaging structuresymmetrically disposed around the optical effective portion andcomprising: an annular surface portion surrounding the optical effectiveportion; and a conical surface located between the annular surfaceportion and the optical effective portion; wherein a width of theconical surface is L2, and the following condition is satisfied:0.07 mm<L2<0.35 mm.
 12. The optical path folding element of claim 11,wherein the optical path folding element is made of a plastic material.13. The optical path folding element of claim 12, wherein the conicalsurface is a closed ring.
 14. The optical path folding element of claim12, wherein an Abbe number of the optical path folding element is V, andthe following condition is satisfied:V<25.0.
 15. The optical path folding element of claim 12, wherein thelight ray is folded by 90 degrees when passing through the path foldingsurface.
 16. The optical path folding element of claim 12, wherein adistance between a center of the incident surface and a center of thepath folding surface is equal to a distance between the center of thepath folding surface and a center of the exiting surface.
 17. An imaginglens module, comprising: the optical path folding element of claim 12.18. An electronic device, comprising: the imaging lens module of claim17.